A space odyssey
Farm News staff writer
DES MOINES – The invisible satellite signals that guide tractors, sprayers and other farm equipment through global positioning system technology have manifested themselves in a high-profile controversy that’s reaching far beyond the farm.
The issue revolves around the push to expand wireless broadband connectivity nationwide, including rural areas, which could come at the expense of GPS. The Virginia-based company LightSquared has applied for a waiver from the U.S. Federal Communications Commission to deploy technology that would dramatically expand broadband access across the United States. As LightSquared builds its state-of-the-art open wireless broadband network, the privately-owned company is using a technology called Long Term Evolution, the most widely adopted 4G standard in the world.
However, extensive testing has shown the technology causes significant disruption with GPS systems, which are well-integrated in the agricultural, construction and aviation industries.
“Allowing LightSquared to implement its network will interfere with the use of GPS in precision applications in agriculture, where America farmers use the technology to restrain the costs of food production while feeding a growing global population,” said Ken Golden, director of global public relations for Deere & Co. “It will also impact millions of Americans who use GPS every day for safe travel in cars and airplanes and it will disrupt the work of soldiers who use GPS receivers in the military.”
LightSquared could knock out thousands of receivers
Deere & Co. has joined a number of other leading companies, including FedEx, Delta Airlines, Garmin, UPS, Caterpillar, Case New Holland, Ag Leader Technology, AGCO and Trimble, in the Coalition to Save Our GPS.
Agriculture groups are heavily engaged on this issue because without a technical fix, LightSquared’s technology would knock out most of an estimated 500,000 precision receivers used in farm equipment, according to the National Association of Wheat Growers.
Coalition members emphasize they are not opposed to the expansion of broadband services.
“We continue to be in favor of expanded broadband coverage for many more Americans, including those in rural America, but we firmly believe that objective should not be met by interfering with the use of GPS that is so vital to millions of Americans,” Golden said. “We believe other proposals to expand broadband coverage and other technologies could make that happen.”
To understand how LightSquared’s technology interferes with GPS signals, it helps to understand some GPS basics. GPS enables users on the ground to determine location by connecting to distant satellites using radio signals. The satellites are more than 12,000 miles away from the user and are solar powered, which necessitates a relatively low-powered radio transmission from space, and in turn drives a need for GPS receivers to be sensitive to the low-powered signals received on Earth, according to the Coalition.
LightSquared’s critics say the service’s powerful signals from thousands of base stations would overwhelm faint emissions from satellites that feed GPS devices, and they charge that LightSquared is using powerful cell towers on frequencies that should only be used by satellites.
LightSquared counters that GPS devices are improperly gathering signals from outside their designated frequency bands.
“LightSquared doesn’t think it owes anyone a fix,” said Charlie Bowman, a GPS and machine control specialist with Star Equipment in Cedar Rapids, who recently spoke at the Iowa Land Improvement Contractors Association’s annual meeting in Des Moines.
LightSquared has one satellite in orbit already and is trying to put a second one in operation, said Bowman, who noted that the second satellite will cost $1.5 million. “No one really knows what will happen if the second one is launched, but it has the potential to block GPS signals.”
Tim Recker, LICA’s state president who farms in northeast Iowa and owns Recker Excavating Inc., is concerned about the LightSquared controversy. “I can’t afford not to have the sub-inch accuracy I’ve paid for with my GPS equipment.”
No resolution yet
A year of testing by a federal interagency committee unanimously determined in mid-January that there “appear to be no practical solutions or mitigations” to GPS interference caused by LightSquared’s broadband technology.
The co-chairs of the interagency review panel, who are deputy secretaries of the U.S. Departments of Defense and Transportation, indicated in a letter to the Department of Commerce that the level of interference, even with proposed fixes, is so severe that “no additional testing is warranted at this time.”
The letter also noted that the Federal Aviation Administration has concluded the technology could interfere with flight-safety systems that depend on GPS. LightSquared reacted quickly, saying the review process was “fraught with inappropriate involvement of the GPS manufacturers, lax controls, obvious bias, lack of transparency and unexplained delays,” and that its private tests have shown its proposed fix for the interference problem “works flawlessly.”
FCC officials have said they will not give LightSquared final approval to launch its network until the company can demonstrate that it has fixed the interference problems. While there is no certainty that LightSquared will get final FCC approval for its network, Golden noted that existing GPS receivers would have to be updated if this approval is granted.
“This impacts what Deere would design for the future,” he said, “but the most current issue is that there are millions of existing GPS receivers in the U.S. that are not protected and would be subject to LightSquared interference.
“High precision receivers such as those used by Deere customers and others in precision applications are particularly sensitive to LightSquared interference. If current GPS receivers need to be modified to filter out interference from the LightSquared network, we believe the cost of such modifications should be the responsibility of LightSquared.”
The ag industry and others who rely on GPS technology are monitoring the LightSquared issue closely. “We will continue to work on behalf of our customers in opposition to this proposal until interference issues are resolved,” Golden said.
For more information on the Coalition to Save Our GPS, log onto saveourgps.org.
Learn more about LightSquared by visiting: www.lightsquared.com.
You can contact Darcy Dougherty Maulsby by e-mail at firstname.lastname@example.org.
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